The present invention relates to a toner cartridge which is to be coupled to the developing unit of an electrophotographic imaging apparatus for supplying toner accommodated therein to the developing device.
Conventionally, an imaging apparatus making use of so-called electrophotography, such as, an electronic copy machine, a laser beam printer, and the like are known, wherein the uniformly charged surface of a photoconductive drum is exposed to light to form a latent image, toner is adhered to the latent image to develop the same into a toner image, and the toner image is transferred to a recording sheet an fixed thereon by a fixing unit.
The developing unit of the imaging apparatus making use electrophotography is arranged such that toner accommodated in a toner accommodating portion is adsorbed by the magnetic adsorbing force of a developing roller and supplied to a development area. Since the toner is consumed by a developing operation, toner must be supplied into the toner accommodating portion as it is consumed.
In many cases, toner is supplied by using a toner cartridge which can be coupled to the developing unit for preventing contamination caused by leaked toner, and making operation of the apparatus simple. More specifically, as shown as an example in FIG. 3 showing a perspective view of a developing unit to which a toner cartridge is coupled, FIG. 4 showing a horizontal cross sectional view thereof and FIG. 5 showing a front view, partly in cross section, thereof, respectively, a cartridge mounting portion 21 is formed on the upper portion of the toner accommodating portion 22 of a developing unit 20, a toner cartridge 10 in which toner is accommodated is mounted on the cartridge mounting portion 21, and the toner falls from the toner cartridge 10 into the toner accommodating portion 22 for replenishment. Although the toner cartridge 10 becomes empty after the toner has been replenished, it serves as a cover for the toner accommodating portion 21 until toner is once again replenished for subsequent use.
The toner cartridge 10, as shown in the drawings has a toner supply port 12 defined on the lower surface thereof and a mounting flange 13 projectingly defined around the outer circumference of the toner cartridge 10. The toner cartridge 10 is mounted on the cartridge mounting portion 21 of the developing unit 20 and is hermetically sealed thereto through a flexible seal member 14, such as a sponge or the like, adhered to the lower surface of the mounting flange 13.
The toner supply port 12 is covered by a tape member 15 adhered along the outer edge thereof in a longitudinal direction. The tape member 15 is bent at the end of the portion where the tape member 15 has finished the closing of the toner supply port and returned to the side from which the toner supply port has been covered. An extreme end 15A of the tape member 15 projects to the outside of the toner cartridge through a slit 14A defined on the seal member 14 and the opening 13A defined on the mounting flange 13. The toner supply port 12 can be opened by pulling the extreme end 15A projecting to the outside of the toner cartridge and removing the tape member 15 at the end thereof where the closing of the toner supply port 12 has been finished.
Nevertheless, with the conventional arrangement as described above, a problem arises in that when the toner supply port 12 is opened by pulling the extreme end 15A projecting to the outside of the toner cartridge and removing the tape member 15 at the end thereof, where the closing of the toner supply port 12 has been finished, the seal member 14 located on the toner supply port 12 side is pulled by the tape member 15, depending upon the portion through which the tape member 15 passes, and is pulled out to the outside of the toner cartridge from the opening 13A and damaged and, thus, the sealing property of the seal member 14 is deteriorated.
More specifically, when the extreme end 15 A of the tape member 15 projecting to the outside of the toner cartridge through the opening 13A is pulled to remove the tape member 15, the tape member 15 is stretched to linearly connect the opening 13A to the edge 12A of the toner supply port 12 from which the toner supply port 12 has been closed as shown in FIG. 6A, so that the flexible seal member 14 is pressed and crushed by the tape member 15 and thus pulled out to the outside of the toner cartridge through the opening 13A and damaged as the seal member 15 moves, as shown in FIG. 6B. As a result, the opening 13A communicates with the toner accommodating portion 22 of the developing unit and toner leaks through the opening 13A.